Prince Charles contemplated calling off his wedding to Princess Diana on the eve of their marriage and told a close confidant that he cannot go through with it,a new biography has sensationally claimed. Catherine Mayer's book 'Charles: Heart of a King' says both Prince Charles and Princess Diana contemplated calling off their wedding -- but for different reasons.While the then Lady Diana Spencer knew the Prince of Wales held affections for Camilla Parker Bowles, her groom panicked that he was rushing into marriage with a girl he hardly knew, The Telegraph quotes the book as saying.